diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2016-04-18 01:16:10 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-06-16 10:48:19 +0200 |
| commit | 1f51dee7ca7424be6f84067395166f878dbdd8be (patch) | |
| tree | 00ee8bbb41a295b4e8299bb51d0e5dcf0229d8b3 | |
| parent | b316ff783d17bd6217804e2e4385ce9347d7dad9 (diff) | |
locking/atomic, arch/alpha: Implement atomic{,64}_fetch_{add,sub,and,andnot,or,xor}()
Implement FETCH-OP atomic primitives, these are very similar to the
existing OP-RETURN primitives we already have, except they return the
value of the atomic variable _before_ modification.
This is especially useful for irreversible operations -- such as
bitops (because it becomes impossible to reconstruct the state prior
to modification).
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-alpha@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
| -rw-r--r-- | arch/alpha/include/asm/atomic.h | 65 |
1 files changed, 56 insertions, 9 deletions
diff --git a/arch/alpha/include/asm/atomic.h b/arch/alpha/include/asm/atomic.h index 572b228c44c7..8243f17999e3 100644 --- a/arch/alpha/include/asm/atomic.h +++ b/arch/alpha/include/asm/atomic.h @@ -65,6 +65,25 @@ static inline int atomic_##op##_return(int i, atomic_t *v) \ return result; \ } +#define ATOMIC_FETCH_OP(op, asm_op) \ +static inline int atomic_fetch_##op(int i, atomic_t *v) \ +{ \ + long temp, result; \ + smp_mb(); \ + __asm__ __volatile__( \ + "1: ldl_l %2,%1\n" \ + " " #asm_op " %2,%3,%0\n" \ + " stl_c %0,%1\n" \ + " beq %0,2f\n" \ + ".subsection 2\n" \ + "2: br 1b\n" \ + ".previous" \ + :"=&r" (temp), "=m" (v->counter), "=&r" (result) \ + :"Ir" (i), "m" (v->counter) : "memory"); \ + smp_mb(); \ + return result; \ +} + #define ATOMIC64_OP(op, asm_op) \ static __inline__ void atomic64_##op(long i, atomic64_t * v) \ { \ @@ -101,11 +120,32 @@ static __inline__ long atomic64_##op##_return(long i, atomic64_t * v) \ return result; \ } +#define ATOMIC64_FETCH_OP(op, asm_op) \ +static __inline__ long atomic64_fetch_##op(long i, atomic64_t * v) \ +{ \ + long temp, result; \ + smp_mb(); \ + __asm__ __volatile__( \ + "1: ldq_l %2,%1\n" \ + " " #asm_op " %2,%3,%0\n" \ + " stq_c %0,%1\n" \ + " beq %0,2f\n" \ + ".subsection 2\n" \ + "2: br 1b\n" \ + ".previous" \ + :"=&r" (temp), "=m" (v->counter), "=&r" (result) \ + :"Ir" (i), "m" (v->counter) : "memory"); \ + smp_mb(); \ + return result; \ +} + #define ATOMIC_OPS(op) \ ATOMIC_OP(op, op##l) \ ATOMIC_OP_RETURN(op, op##l) \ + ATOMIC_FETCH_OP(op, op##l) \ ATOMIC64_OP(op, op##q) \ - ATOMIC64_OP_RETURN(op, op##q) + ATOMIC64_OP_RETURN(op, op##q) \ + ATOMIC64_FETCH_OP(op, op##q) ATOMIC_OPS(add) ATOMIC_OPS(sub) @@ -113,18 +153,25 @@ ATOMIC_OPS(sub) #define atomic_andnot atomic_andnot #define atomic64_andnot atomic64_andnot -ATOMIC_OP(and, and) -ATOMIC_OP(andnot, bic) -ATOMIC_OP(or, bis) -ATOMIC_OP(xor, xor) -ATOMIC64_OP(and, and) -ATOMIC64_OP(andnot, bic) -ATOMIC64_OP(or, bis) -ATOMIC64_OP(xor, xor) +#define atomic_fetch_or atomic_fetch_or + +#undef ATOMIC_OPS +#define ATOMIC_OPS(op, asm) \ + ATOMIC_OP(op, asm) \ + ATOMIC_FETCH_OP(op, asm) \ + ATOMIC64_OP(op, asm) \ + ATOMIC64_FETCH_OP(op, asm) + +ATOMIC_OPS(and, and) +ATOMIC_OPS(andnot, bic) +ATOMIC_OPS(or, bis) +ATOMIC_OPS(xor, xor) #undef ATOMIC_OPS +#undef ATOMIC64_FETCH_OP #undef ATOMIC64_OP_RETURN #undef ATOMIC64_OP +#undef ATOMIC_FETCH_OP #undef ATOMIC_OP_RETURN #undef ATOMIC_OP |